Ultra short wave radio receiver



M. BLY

ULTRA SHORT WAVE RADIO RECEIVER- Dec. 31, 1940;

Original Filed June 6, 1938 IN V EN TOR. 3%

Patented Dec. 31, 1940 t h TES rem OFFICE ULTRA SHUR'E" WAVE RADIO RECEIVER Merwyn Bly, Leesburg, Va.

Application June 6,1938, Serial No. 212,154

' Renewed May 13, 1940 11 Claims. (01. 250-20) This invention relates to radio signal receivers erate as a super-regenerative detector tube. The in general, More particularly this invention recurrent to the plate of this detector tube is fed lates to radio signal receivers adapted for use with thereto through a novel circuit arran radio frequencies known as ultra high frequencies. which perm t Supe e e erative action of An object of this invention is to produce an thist e t controlled nd/or stopped an ,5 ultra high frequency radio receiver of very high furthermore enables the operator to control the sensitivity and with a minimum of so called backqu n hi f qu y o t s tube s t at a pground noise. timum frequency may be selected for different Another object of this invention is to provid frequency signals to be received' Enormous aman ultra high frequency radio receiver employp fiee e s pro y this t e ab the 10, ing the super-regeneration principle and a novel reception Of y Week signelseV ould circuit arrangement for adjusting the circuit. i it be desired to receive signals of substantial in- Still another object of this invention is to prot n y for Which this amplification s not eevide an ultra high frequency radio receiver emessary, t super-re a v action of t e de- 15 ploying a circuit arrangement which may be made ec r may be stopped y s plate current con- 15 to function simply as a regenerative or as a super-e trol as W ll e cxplainedin detail hereinafter and regenerative receiver at will. 1 the detector operated simply as a regenerative A further object of this invention is to provide deteetOra radio receiver adapted for use with ultra high Further details of this invention Will be pradio frequencies, employing a novel' coupling cir parent from the following Specification and the 20 cuit arrangement between the ultra high fredrawing in which the sole figure illustrates quency detector and an amplifier whereby said schematically a circuit arrangement incorporatdetector may be operated as a super-regenerative ihg y ihventiehv tub for receiving 11- high frequency i s, Referring to the drawing in detail reference Another object of thisinvention is to provide numeral designetesetiiede Vacuum tube which 25 a radio receiver adapted for the efficient recepy e 01 the type commercially designated as tion of ultra high frequency radio signals and 6 ThiS type of tube is norma y p v ded W th employing a variable resistance control for varya metal Shield that Should be connected to the ing the fi t f th upern ati ti 'i metal chassis or frame of theradio receiving set;

59 the circuit, The tube I0 is provided with a grid H, an indi- Still another object of this invention is to pror ctly heated cathode l2 and a plate or node i 3'.

vide a variable resistance super-regeneration con The grid H is connected to the grid leak a d grid trol in a radio receiver, said variable resistance condenser I 4, l5 and through these to the tuned being also adapted to function as a part of an circuit including the inductance l6 connected in inter-tube coupling circuit. I parallel; with the variable condenser l1. The 35 Other and further objects of this invention anode I3 is connected to the aforesaid tuned cirwill be apparent from the following specification cuit at the end opposite to that to which the grid and c1ajm5 a h a 3 a H is connected. I In accordance with this invention 1 provide a A Small a a c up Coil 5 is coupled 40 radio receiver circuit arrangement that is ext t e a de e d of the inductance It for in- 40 tremely sensitive and efficient in the reception .ductively orotherwise impressing radio signal of ultra high radio frequency signals. energy upon the circuits of the tube It. The The receiving system of. my invention is es coupling coil lea is connected to any suitable pecially useful for receiving ultra high frequency type of antenna, adapted for receiving ultra high signals although the same system may be adapted frequency signals, by means of the wires I62). 45

to othe frequencies ifdesired, These Wires Nib arecovered by insulation and r 7 Among the main featuresof my invention are ed n O der to minimize their adaptability the ease with which the receiver. is adjusted and for picking up interference and transmitting used and the sensitivity that it possesses whereby such interference to the coupling coil. f It is of to signals not heard on conventional receivers may urse Obvious that the wires lfzbmaybe made be received on it with good signal strength. up in the nature of a concentric cable in which i The first detector ;tube of my radio receiver, case the outer member 0f the concentric cable in cases where my invention is incorporated into functioning as one of these wires is preferably a superheterodyna'is arranged to produce the grounded. Furthermore both of the wires [6bquenching oscillations enabling this tube to 0py e positioned: inside of a ded metal 55 conduit and in that case of course both of these wires would be insulated from the metal conduit although they may be connected by suitable de-' vices, such as, one or more inductances or capacities to the metal conduit.

It is, of course, obvious that one or more stages of radio frequency amplification using the screen grid acorn type tube may be used between the antenna circuit and the circuit of the detector l so as to isolate the antenna from the detector to prevent radiation of frequencies developed in the detector circuits and to facilitate and stabilize the control of the regenerative or super-regenerative action of the detector.

A tap H3 is provided to the inductance IS and the inductance coil I0 is connected to this tap. The condenser 20 is connected to the inductance I9 and to the cathode |2 of the tube Hi. This condenser 20 and inductance i9 are arranged to cooperate together and with the other elements associated with the tube forproducing superregenerativeaction in the vacuum tube circuit.

This super-regenerative action may be controlled by the variable resistor or potentiometer 2| provided with a variable contact 22 which is connected to the inductance I9 and condenser 20 in such a way that it may be used to control the amount of the potentiometer resistance connected'across the condenser 20. For example, when the contact 22 'is moved toward the end 2|a. of the potentiometer the condenser 20 is virutually short-circuited through a low resistance connection. However, when the contact 22 is moved toward the end 2H2 of the potentiometer considerable resistance is shunted or connected across this condenser 20.

I have found that this arrangement of varying the resistance shunted across the condenser 20 possesses very desirable characteristics and is extremely usefulfor controlling the super-regenerative action of the tube Hi and in controlling the frequency of the quenching oscillation Another resistance 23 is connected in series with the potentiometer 2| in sucha way that the anode current for the tube It! passes through this resistance 23. The signal output from the tube 19 is impressed upon a control grid of the multigrid tube 28. through the coupling condenser 26 and across the grid resistor 21 connected to this control grid. The tubes 28 and 29 are both of the 6K7 type connected in cascade to function as intermediate frequency amplifiers and produce an-enormous amplification of the signal modulated voltage. The output circuit of the tube 28 includes a plate resistor, which is connected to the positive terminal of'the anode current supply. and a suitable coupling condenser for impressing nergy from the output of tube 28 on a control grid of the tube 29 whereby the signal fed to tube 29 is impressed across the grid resistor of this tube and across a filter circuit 30; circuit includes a choke coil 3011, a condenser 30b and a variable resistor 30c and has a definite peak at thehigh frequency end of the audio frequency spectrum for the purpose of absorbing interference noises occurring in the form of hissing which appears to have a definite relationship to the quenching frequency or frequencies. I have also found that the operation of this filteris most efiicient and beneficial for this purpose when the filter is connected across the grid resistor of the tube 29.

A variable resistor 3| is also connected in the circuit of the cathode of the tubes 28 and 29 for the purpose of varying the biasing potential of This filter these cathodes with respect to the control or other grids of the tubes 28 and 29 or vice versa. If desired a separate control such as the resistor 3| may be provided to each of the tubes 28 and 29 whereby this control may be adjusted for these tubes individually,

Signal modulated energy obtained from the output of the amplifier tube 29 is impressed upon the input of the detector tube 32 which is of the triode type and is coupled to the input circuit of the audio frequency amplifier consisting of the 7 tubes 33 and 34. The tube 33 is also of the triode type. however, the tube 34 is of a multi-grid type commercially designated 6V6G. The signal modulated energy is impressed upon the control grid 35 and the cathode 36. The output circuit which may consist of the primary of a transformer or of a suitable winding or windings of a reproducing device or of any other signal energy utilizing circuit. is connected to the anode 31 and gride electrode 38.; The gride electrode 38 is connected to the positive terminal of the anode current supply and a small condenser 39 is connected between the-anode and the conductor 25 which is connected to the metal chassis, to the negative terminal of the anode current supply and to the cathode circuits of the various tubes comprising the receiving circuit. Any conventional type of anode current supply may be employed on this radio receiving circuit. The cathode heaters of the various tubes also may be energized from any type of electric current supply although the use of a small alternating current transformer is perha s the most economical for this purpose.

While I do not desire to be limited to any particular values or sizes of parts or circuit components employed in the radio receiving circuit set forth in this specification except insofar as such sizes or values may be set forth in the. claims, I have found that the following elements when made of the following sizes or values. respectively, produce exceptionally good results in the reception of radiosignals of approximatelv meters wave length. The inductance l6 should consist of approximately 6 turns of inch diameter well spaced and the tap I8 should be positioned approximately 2 turns away from the grid end of thecoil. The condenser I! should of course be of such a size as to tune the inductance to the 5 meter or other high frequency signals to be received. A relatively high resistance grid leak Min theneighborhood of megohms should be employed with the tube designated; The inductance |9 should consist preferably of about 40 turnswound in a single layer on a 4. inch diameter form using wire of approximately No. 28 A. W. G. and the condenser should be approximately 0.005 .micro-farad capacity. The potentiometer 2| may have a total resistance of 30,000 to 50,000 ohms and for the values given the resistance between the end,,2|a and the tab 22 should bearound 15.000 ohms. At this approximate value the super-regenerative action obtained produces the most satisfactory signal reception. The resistance, 23 in series with th p tentiometer 2| is approximately 50,000 ohms. The inductance a and capacity 30b of the filter 30 are of a'size necessary to produce resonance in this circuit at the upper end of the audio frequency spectrum. Of -course if this circuit is to be used to filter other frequencies the values of these units will necessarilyhave to be adjusted accordingly." The variable resistance 300 which is used to control the effect-of the filter is of 75,000 ohms maximum resistance. The maximum resistance of "the variable resistor 3| is 10,000 ohms. The size of the condenser 39 is approximately 0.0lmicro-farad.

The'operation of this radio receiving circuit is as follows: The variable contact 22 of the potentiometer Zlis adjusted so that super-regenerative action is obtained in the circuit of the tube l0, and the variable condenser H is varied In order to tune the circuit consisting of the inductance l6 and this condenser IT to the frequency' which it is desired to receive. At the same time the coupling between the antenna coil I So and the inductance I6 is varied to obtain maximum sensitivity and efficiency. Should the super-regenerative action stop or become weak during the tuning operation then the position of the tap 22 is adjusted to produce or increase this action. When the received signal'is accompanied by a relatively loud hissing noise then the action of the filter 30 is increased by decreasing the size of the resistance 30c so that the absorption circuit is given an opportunity to absorb the interfering noise or noises. Where desired either one or both the inductance 30a and the condenser 30?) may be made variable to enable the operator to adjust this absorption circuit to other interference frequencies that may be present. More than one of these absorption circuits may be used, each having difierentfrequency characteristics, if desired.

While I have described a certain embodiment of this invention in detail it is of course understood that modifications of the invention may be made without departing from the spirit and scope of the invention and therefore I do not desire to limit this invention to those exact details except insofar as they may be defined by the claims.

' What I claim is:

1. Radio receiving apparatus adapted for reception of ultra high frequency signals of the order of five meters wavelength, comprising: a vacuum tube adapted to function as a super-regenerative detector, a source of anod current supply for said detector, means for producing quenching oscillations for said detector tube, said means including an oscillatory circuit and a variable resistance device connected to shunt one of the elements of said oscillatory circuit for controlling the production of the quenching oscillations, at least a portion of said variable resistance device being connected in series with said anode current supply, means for impressing signal modulated energy on said detector and amplifying and signal reproducing means connected to said detector.

2. Radio receiving apparatus adapted for reception of ultra high frequency signals of the order of five meters wavelength, comprising: a vacuum tube adapted, to function as a super-regenerative detector, a source of anode current supply for said detector, means for producing quenching oscillations for said detector tube, said means including an oscillatory circuit and variable impedance means connected to shunt one of the elements of said oscillatory circuit for controlling the production of the quenching oscillations, at least a portion of said variable impedance means being connected in series with said anode current supply, means for impressing signal modulated energy on said detector and amplifying and signal reproducing means connected to said detector.

3. Radio receiving apparatus adapted for reception of ultra high frequency signals of the rent supply;

order of five meters wavelength, comprisingr'a vacuum tube adapted to function as a super-regenerative detector, a source of anode current supply for said detector, means for producing quenching oscillations for said detector tube, said means comprising an oscillatory circuit including inductance and capacity elements and variable impedance means connected to shunt'one of'the elements of said oscillatory circuit for controlling the production of the quenching oscillations, at least a portion of said variable impedancemeans being connected in series with said anode current supply, means for impressing signal modulated energy on said detector and amplifying and signal reproducing means connected to said detector. I

4. Radio receiving apparatus adapted for reception of ultra high frequency signals of the order of five meters wavelength, comprising: a vacuum tube adapted to function as a superregenerative detector, a source of anode current supply for said detector, means for producing quenching oscillations for said detector tube, said means comprising an oscillatory circuit including inductance and capacity elements and a variable resistance device connected to shunt said'capacity element of said oscillatory circuit for controlling the production of the quenching oscillations, at least a portion of said variable resistance device being connected in series with said anode current supply, means for impressing signal modulated energy on said detector and amplifying and signal reproducing means connected to said detector.

5. Radio receiving apparatus adapted forreception of ultra high frequency signals of theorder of five meters wavelength, comprising: a vacuum tube having a cathode, grid electrode and an anode and adapted to function as a super-re generative detector; a source of anode current supply for said detector, an antenna circuit; a tuned circuit connected between the grid and anode of said vacuum tube; means for impressing signal modulated energy from said antenna circuitupon said tuned circuit; an oscillatory circuit including an inductance and a capacity; means for connecting said oscillatory circuit to said tuned circuit for producing quenching oscillations for said vacuum tube; a variable resistance device having a variable portion adapted to be connected across one of the elements of said oscillatory circuit for controlling the production of said quenching oscillations; connections for connecting the resistance element of said variable resistance device across said source of anode cursignal reproducing means and means for impressing signal modulated energy from said vacuum tube on said signal reproducing means.

6. Radio receiving apparatus adapted for reception of ultra high frequency signals of the order of five meters wavelength, comprising: a vacuum tube having a cathode, grid electrode and an anode and adapted to function as a superregenerative detector; an antenna circuit; a tuned circuit connected to the electrodes of said vacuum tube; means for impressing signal modulated energy from said antenna circuit upon said tuned circuit; an oscillatory circuit includ ing an inductance and a capacity; means for connecting said oscillatory circuit to said vacmeans for varying the magnitude of said variable resistance device connected across said capacity for controlling the production of said quenching oscillations; a source of anode current supply for said detector connected to said variable resistance device, a portion of said variable resistance device other than the portion connected across said capacity being connected in series with said source of anode current, a signal reproducing means and-means for impressing signal modulated energy from said vacuum tube on said signal reproducing means.

7. Radio receiving apparatus adapted for reception of ultra high frequency signals of the order of five meters wavelength, comprising: a vacuum tube having a cathode, grid electrode and an anode and adapted to function as a super-regenerative detector, an antenna circuit, a tuned circuit connected to the electrodes of said vacuum tube, means for impressing signal modulated energy from said antenna circuit upon said tuned circuit, an oscillatory circuit including an inductance and a capacity, means for connecting said oscillatory circuit to said vacuum tube for producing quenching oscillations for said vacuum tube, a variable resistance device connected across said capacity of said oscillatory circuit; means for varying the magnitude of said variable resistance device connected across said capacity for controlling the production of said quenching oscillations; an intermediate frequency amplifier; a coupling circuit including said variable resistance device for connecting said intermediate frequency amplifier to said vacuum tube detector; an absorption circuit tuned to absorb hissing interference frequencies produced by said super-regenerative detector connected to said intermediate frequency amplifier; signal reproducing means and means for impressing signal modulated energy from said amplifier on said reproducing means. I

8. Radio receiving apparatus adapted for reception of ultra high frequency signals of the order of five meters wavelength, comprising: a vacuum tube having a cathode, grid electrode and an anode and adapted to function as a superregenerative detector, an antenna circuit, a tuned circuit connected to the electrodes of said vacuum tube, means for impressing signal modulated energy from said antenna circuit upon said tuned circuit, an oscillatory circuit including an inductance and a capacity, means for connecting said oscillatory circuit to said vacuum tube for producing quenching oscillations for said vacuum tube, a variable resistance device adapted to have varying portions thereof connected across said capacity of said oscillatory circuit for controlling the produtcion of said quenching oscillations; an intermediate frequency amplifier; a coupling circuit including at least a portion of said variable resistance device for connecting the output of said detector tube to the input of said amplifier; signal reproducing means and means for impressing signal modulated energy from said vacuum tube on said signal reproducing means.

9.,Radio receiving apparatus as set forth in claim 2 further characterised in that said amplifying means comprises ,a pair of amplifier tubes and substantially aperiodic coupling means between said tubes and means for reducing interference frequencies resulting from the operation of said detector as a super-regenerative detector. r

10. Radio receiving apparatus as set forth in claim 2 further characterisedin that said amplifying means comprises a pair of multiple grid amplifying tubes and substantially aperiodic coupling means between said (tubes and means for reducing interference frequencies resulting from the operation of said detector as a super-regenerative detector. l

11. Radio receiving apparatus asset forth in claim 2 further characterised in that said amplifying means comprises a pair of multiple grid amplifying tubes and substantially aperiodic coupling means for connecting said tubes in cascade and a series resonant absorption circuit connected to the input circuit of the second of said amplifying tubes for reducing the noise level of the quench frequency of said detector.

MERWYN' BLY. 

